Follow this link "Armed robbers loot ancient Greek museum" to view a video about the theft of the Museum of the History of the Olympic Games on February 17, 2012. ARCA Instructor Dick Ellis is quoted in the accompanying article (excerpts here):

As a pair of armed robbers bound and gag a security guard to steal dozens of ancient artifacts from the Olympia museum in Greece, Channel 4 News goes hot on the trail of the illicit antiquities trade.
"It has become an organised crime business," said Richard Ellis. A former Scotland Yard detective who set up the Metropolitan Police's Art and Antiques Squad, the specialist art and antiquities crime investigator has worked on the recovery of some of the world's most famous paintings, including Edvard Munch's The Scream.

The latest known theft to have taken place only happened this morning, when two armed robbers broke into an Olympia Museum and made off with between 60 to 70 bronze and clay pottery objects. They tied up and gagged the female security guard before using hammers to smash display cases and grab the loot.
That followed the theft last month of a Picasso and a Mondrian from the capital's National Gallery. Today's incident prompted the culture minister, Pavlos Geroulanos, to tender his resignation, amid outcry that the nation's priceless treasures were no longer safe in state hands.
Now, Mr Ellis told Channel 4 News, "the incentive is there to make money in Greece". And they may well begin a life which sees them travel from the poorer hands of the lowly thieves who broke into the museum to reach the lucrative shores of London or New York, and in some cases, find themselves auctioned off for tens of millions of dollars.
"I am sure the current economic situation is Greece is triggering people to become more active," Mr Ellis said. "I would expect these objects are going to get moved. It's a transitional country for other stolen goods, and they can go west or east."

According to Mr Ellis, many are looted or excavated by poorer local people looking to make some fast yet small amounts of cash, before being sold on to intermediaries.
The real mark up, he says, comes in the stage after that, after they have been passed on to dealers. From here they can end up in auction houses or with private collectors, having changed hands for millions of dollars.
In some cases, Mr Ellis said, collectors are aware they are trading in illegal goods, despite a rise in 'due dilligence' to establish the provenance of items.

The article also includes a perspective from Christos Tsirogiannis, [a contributor (along with David Gill) to ARCA's Journal of Art Crime] a researcher in illicit antiquities and repatriation cases at Cambridge University, and a former archeologist with the Greek police squad.

"All the countries that are in decline, with financial problems, and yet hosted ancient civilisations, such as Greece, Italy and Egypt - they are going to see big problems. In Greece, this is connected with the financial situation. We will have more of such things coming up in the next few months. The people who stole this are uneducated people with no money, who are not aware it will be difficult to give these objects to the market as they are recorded, and there are pictures of them. They do it for money, but they are not aware it will be really difficult to get rid of them."
It may be the case that some of them end up in refrigeration trucks transporting food in order to be smuggled across borders, through Turkey and the former Yugoslavia, before reaching Europe where they are likely to fetch up a higher price.
Another popular route for other goods illegally seized or excavated from Asia, Mr Tsirogiannis said, is aboard ships to Italy. From there they may make their way to Switzerland, and from there, he said, they may be laundered in auctions in London and New York before being sold to private museums and collectors.